Most of integrated electronic circuits (e.g., microprocessors, memory devices, application specific integrated circuits (ASICS), and the like) require several power supplies, where each power supply provides one or more supply voltages. In operation, such voltages should be applied to and removed from the electronic circuits in pre-determined orders, or sequences. Violation of such sequences may result in damaging an electronic circuit.
Conventionally, banks of pre-charged capacitors are used as emergency sources of energy to protect the electronic circuits from accidental loss of a supply voltage as a result of, e.g., a failure of the respective power supply. Such capacitors temporarily substitute for the loss of a supply voltage for the duration of time needed to execute a pre-determined emergency sequence for powering down the affected electronic circuit. However, in advanced electronic circuits using low supply voltages and consuming high supply currents, the number and dimensions of such capacitors become prohibitively large.
Therefore, there is a need in the art for an improved method and apparatus for powering electronic circuits.